On Mon, 4 Aug 2025 08:00:00 +0200 Marco Elver <el...@google.com> wrote:
> > The load-acquire pairs with the write memory barrier > > used in kcov_move_area() > > > > Signed-off-by: Soham Bagchi <soham.bag...@utah.edu> > > Reviewed-by: Marco Elver <el...@google.com> > > > --- > > > > Changes in v2: > > Btw, it is customary to send out the whole patch series on a version > bump, even if only one of the patches changed. > https://www.kernel.org/doc/html/latest/process/submitting-patches.html#explicit-in-reply-to-headers Yes please, try to keep everything together. We look at a lot of patches! I queued this as a -fix against the original https://lkml.kernel.org/r/20250728184318.1839137-2-soham.bag...@utah.edu --- a/Documentation/dev-tools/kcov.rst~kcov-load-acquire-coverage-count-in-user-space-code-v2 +++ a/Documentation/dev-tools/kcov.rst @@ -287,11 +287,6 @@ handle instance id. The following program demonstrates using KCOV to collect coverage from both local tasks spawned by the process and the global task that handles USB bus #1: -The user-space code for KCOV should also use an acquire to fetch the count -of coverage entries in the shared buffer. This acquire pairs with the -corresponding write memory barrier (smp_wmb()) on the kernel-side in -kcov_move_area(). - .. code-block:: c /* Same includes and defines as above. */ @@ -366,6 +361,11 @@ kcov_move_area(). */ sleep(2); + /* + * The load to the coverage count should be an acquire to pair with + * pair with the corresponding write memory barrier (smp_wmb()) on + * the kernel-side in kcov_move_area(). + */ n = __atomic_load_n(&cover[0], __ATOMIC_ACQUIRE); for (i = 0; i < n; i++) printf("0x%lx\n", cover[i + 1]); _
